NEW MATERIAL:A compound shown by the formula I (X is H, or halogen; R is H, or lower alkyl; Y is group shown by the formula II or group shown by the formula III).

EXAMPLE: 1,3,4,5,6,7-Hexahydro-2,5-benzothiazonin.

USE: A drug for circulatory system. Having an inhibitoy action on blood platelet aggregation, an inhibitory action on contraction of extracted intestine, vasodilating action on crown blood, etc.

PREPARATION: A phenylthiomorpholin-3-one shown by the formula IV is reacted with a methyl halide such as methyl iodide, methyl bromide, etc. and silver perchlorate, silver 4-fluoroborate, Meerwein reagent, etc. to give a methylsulfonium salt shown by the formula V (Z is inorganic anion). It is heated in the presence of a base (e.g., sodium amide, etc.) to give a compound shown by the formula I .